Neurofibromatosis (NF) is the genetic change that results in the development of benign tumors around the nerves of the body. It can also affect the bones, vision and various other systems of the body. There are three types of neurofibromatosis; NF1, NF2 and schwannomatosis. Neurofibromatosis type 1 is the common form of NF that is estimated to affect around 1 in every 3,000 births. This type is characterized by the presence of café au lait skin spots and small benign tumors on or under the skin. In some cases, the tumors can develop in the brain or arise in the spinal nerves. Although most of the cases present the benign (noncancerous) tumors, it can cause complications by pressing on the nearby tissues resulting in its associated symptoms.
Causes
A genetic mutation in the gene NF1 is responsible for the cause of this condition. This gene is responsible for the production of a protein known as neurofibromin that is normally produced in several cells including the nerve cells and other specialized cells surrounding the nerves. This protein functions as a tumor suppressor preventing the cells from growing out of control and dividing rapidly. The genetic mutation results in the nonfunctional protein that cannot control the cell growth and division. NF1 is inherited in an autosomal dominant pattern meaning a single defective gene in each cell can cause this condition.
Symptoms
Neurofibromas are the lumps on or under the skin which can cause itching and pain. The neurofibromas can range from only a few in numbers to a severe form presenting thousands. A less common form of neurofibroma is the plexiform neurofibroma that can continue to grow large causing problems such as pressure on the nerves and organs. In some cases, these benign tumors have the potential to become malignant. Additional symptoms of NF1 include café au lait spots on the skin, learning difficulties in around 50% of the children, delayed or early puberty, small stature and high blood pressure which is one of the serious complications of NF1. An optic glioma is the tumor that can develop in the nerve behind the eye which mostly does not cause any symptoms and requires no treatment although in some case it can affect vision.
Diagnosis
The diagnosis is based on the physical examination, the symptoms and with various tests. Although the pigmentation of the skin can be evident at the birth of the infant, additional signs may not be apparent until childhood. The clinical diagnosis is usually based on the identification of any two of the features of the condition. A genetic testing can also help confirm the diagnosis by detecting the mutation responsible for the development of the disorder.
Treatment
There is no cure for the condition but the treatment is based on the symptoms evident in each case. The primary treatment options for the tumors are observation and evaluation. When the tumors present problems, surgery may be considered. Alternatively, radiation therapy and chemotherapy may both be used for the treatment of some of the tumors. Genetic counseling may be beneficial for some of the affected individuals and their family members.
References
https://ghr.nlm.nih.gov/condition/neurofibromatosis-type-1#inheritance
http://www.ctf.org/images/uploads/CTF-NF_Newly_Diagnosed_Brochure_V11.pdf
http://www.ctf.org/understanding-nf/nf1
https://www.nfauk.org/what-is-neurofibromatosis/nf-type-1
